| 摘要 |
PROBLEM TO BE SOLVED: To suppress friction between a reel press and a lock-releasing member in a single-reel type magnetic tape cassette in which a reel locking mechanism is provided between an inner bottom of a boss of a reel and an upper case, thereby preventing plastic powders from being generated and resulting in improved reliability of the tape cartridge. SOLUTION: Between an inner bottom of a boss 12 of a reel 2 and an upper case 1a, a reel press 16 for preventing the reel 2 from freely rotating and a spring 17 are provided. The reel press 16 rotates in an unrotatable manner to be held. In order to push the reel press 16 upwardly against a biasing force caused by the spring 17 to release a reel locking condition, a lock-releasing member 18 is provided between the reel press 16 and the inner bottom of the boss 12. The lock-releasing member 18 rotates along with the reel 2. A socket section 25 is provided on a lower surface of the reel press 16, and a ball 26 is rotatably fitted into the socket section 25. The ball 26 comes into contact with the lock-releasing member 18, and rotates along with the lock-releasing member 18 when the reel rotates. Friction is reduced by means of rolling friction of the ball 26.
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